Survival analyses of breast cancer patients--the Shaukat Khanum Memorial experience.

ABSTRACT

Seven hundred subjects with breast cancer malignancies were followed up in time from December 1994 to December 2002 to determine survival distributions between sub-groups of breast cancer patients who had undergone surgical resection of the tumor followed by adjuvant treatment. Tumor size, nodal status, and Estrogen Receptor (ER) status at the time of presentation were ascertained. Tumors were classified according to the TNM system of the American Joint Committee on Cancer (AJCC), sixth edition, and grouped into T1/T2 and T3/T4; lymph nodes were categorized as N0 (node-negative) and N1, N2, and N3 combined (node-positive). The endpoint of interest for disease-free survival was relapse, and for overall survival, it was death. The Wilcoxon statistics for testing the equality of disease-free survival distributions between groups of patients with tumor size greater than 5 versus less than or equal to 5 cm, node-positive versus node-negative, and ER-positive versus ER-negative were found to be statistically significant (p < 0.05). For overall survival, substantial differences were found between groups of patients stratified according to tumor diameter and nodal involvement, but none for ER status.